This invention relates generally to sewing machines and more particularly, to a method and apparatus for holding a mattress label while it is being sewn to a mattress panel.
Manufacturers are particularly concerned that high quality products portray a high quality image. To this end, identifying labels are preferably made of a high quality material and attached to the product in a high quality manner. In the mattress field, mattress companies have specifications regarding the appearance and the attachment of the label. Among these is the requirement that the outer edge of the label must be securely sewn to a top panel of the mattress. In addition, the label should not have trim tails or other unsightly features.
Label sewing machines are known. One such machine is disclosed in U.S. Pat. No. 5,520,129 entitled xe2x80x9cMethod and Apparatus for Join and Sew Applicationxe2x80x9d. With such a machine a mattress label is placed in a frame and held therein by pins or tacks located at each corner of the frame. While the tacks function well to hold the label, it requires mental focus and manual dexterity to manipulate each small corner of the label such that it is properly secured to a respective tack. When performed repeatedly over periods of time, such an operation can be stressful and prone to error. In addition, a corner of the label may accidently come off of its respective tack. Whether from an improper loading of the label or an accidental release of a label corner, a loose label corner often results in the label not being properly sewn on the mattress. Manually removing and/or resewing the label on the mattress panel is labor intensive and expensive.
Therefore, there is a need for a better way to more reliably secure the mattress label while it is being sewn on a mattress panel.
The present invention provides a clamping system for a sewing machine that reliably secures the mattress label while it is being sewn on a mattress panel. The clamping system of the present invention is easier to use and therefore, leads to a faster and more reliable placement of the mattress label in the sewing machine. Thus, the clamping system of the present invention is especially useful in a production environment where its ease of use and reliability help to substantially relieve sewing machine operator stress in the process of sewing a label to a product. Further, the clamping system of the present invention substantially reduces rework or resewing of a label and therefore, provides a more efficient and cost effective label sewing operation.
According to the principles of the present invention and in accordance with the described embodiments, the invention provides a clamping system for a sewing machine. The sewing machine has a frame and an opening in the frame for receiving a first material that is to be sewn with the sewing machine to a second material. The clamping system has a plurality of clamps mounted adjacent the opening in the frame. Each of the clamps has a stationary member, a movable member and an actuator. The actuator is connected to the movable member and operates to move the movable member in a clamping relationship with the stationary member to clamp the first material in the clamp.
In one aspect of the invention, the clamp is powered by a cylinder with a linear stroke, the clamp has a driving member that transfers the linear motion of the cylinder into a pivoting motion of the movable member. Further, the movable and fixed members have forward ends shaped so that they hold the first material but do not interfere with a sewing of the first material to the second material.
In another embodiment of the invention, a method of securing a stitchable material in a sewing machine having a frame and an opening in the frame for receiving the stitchable material. First, an edge of the stitchable material is located between a movable member and a fixed member of a clamp mounted adjacent the opening. Next, the movable member is moved toward the stationary member to clamp the edge of the stitchable material between the movable and the stationary members. In one aspect of this invention, a driving member is translated by an actuator and raises a rearward end of the movable member, thereby pivoting a forward end of the movable member against a forward end of the stationary member.